This Time Self-Hosted
dark mode light mode Search

Dexcom G6: new phone and new sensor

In the previous posts on the Dexcom G6, I’ve talked about the setup flow and the review after a week, before the first sensor expired. This was intentional because I wanted to talk about the sensor replacement flow separately. Turns out this post will also have a second topic to it, which came by by chance: how do you reconfigure the app when you change phone or, like it happened to me this time, when you are forced to do a factory reset.

I won’t go into the details of why I had to do a factory reset. I’ll just say that the previous point about email and identities was involved.

So what happens when the Dexcom is installed on a new phone, or when you have to reinstall this? The first thing it will ask you is to login again, which is the easy part. After that, though, it will ask you to scan the sensor code. Which made no sense to me! I said “No Code”, and then it asked me to scan the transmitter code. At which point it managed to pair with the transmitter, and it showed me the blood sugar readings for the past three hours. I can assume this is the amount of caching the transmitter can do. If the data is at all uploaded to Dexcom system, it is not shown back to the user beside those three hours.

It’s important to note here that unless you are at home (and you kept the box the transmitter came with), or you have written down the transmitter serial number somewhere, you won’t be able to reconnect. You need the transmitter serial number for the two of them to pair. To compare again this to the LibreLink app, that one only requires you to log in with your account, and the current sensor can just be scanned normally. Calibration info is kept online and transmitted back as needed.

A few hours later, the first sensor (not the transmitter) finally expired and I prepared myself to set the new one up. The first thing you see when you open the app after the sensor expired is a “Start new Sensor” button. If you click that, you are asked for the code of the sensor, with a drawing of the applicator that has the code printed on the cover of the glue pad. If you type in the code, the app will think that you already set up the whole sensor and it’s ready to start, and will initiate the countdown of the warm up.

At no point the app direct you to apply the new sensor. It gives you the impression you need to first scan the code and then apply the sensor, which is wrong!

Luckily despite this mistake, I was able to tell the app to stop the sensor by telling it I’d be replacing transmitter. And then re-enrolling the already present transmitter. This is all completely messed up in the flow, particularly because when you do the transmitter re-enrolment, the steps are in the correct order: scan then tell you to put the transmitter in, and then scan the transmitter serial number (again, remember to keep the box). It even optionally shows you the explanation video again — once again, totally unlike just starting a new sensor.

To say that this is badly thought out is an understatement to me. I’ll compare this again with the LibreLink app that, once the sensor terminates, actually shows you the steps to put on a new sensor (you can ignore them and go straight to scanning the sensor if you know what you’re doing).

On the more practical side, the skin adhesive that I talked about last week actually seems to work fine to keep the sensor in place better, and it makes dealing with my hairy belly simpler by bunching up the hair and keep it attached to the skin, rather than having it act as a fur against the sensor’s glue. It would probably be quite simpler to put on if they provided a simpler guide on the size of the sensor though: showing it on the video is not particularly nice.

The sensor still needed calibration: the readings were off by more than 20% at first, although they are now back on track. This either means the calibration is off in general, or somehow there’s a significant variation between the value read by the Dexcom sensor and the actual blood sugar. I don’t have enough of a medical background to be able to tell this, so I leave that to the professionals.

At this point, my impression of the Dexcom G6 system is that it’s a fairly decent technical implementation of the hardware, but a complete mess on the software and human side. The former, I’m told can be obviated by using a third-party app (by the folks who are not waiting), which I will eventually try at this point for the sake of reviewing it. The latter, probably would require them to pay more attention to their competitors.

Abbott seems to have the upper-hand with the user-friendly apps and reports, even though there are bugs and their updates are very far in between. They also don’t do alerts, and despite a few third-party “adapters” to transform the Libre “flash” system into a more proper CGM, I don’t think there will be much in the form of reliable alerts until Abbott changes direction.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.